Enhance DisMaxQParserPlugin to support full-Solr syntax and to support alternate escaping strategies.

Details

Description

The DisMaxQParserPlugin has a variety of nice features; chief among them is that is uses the DisjunctionMaxQueryParser. However it imposes limitations on the syntax.

I've enhanced the DisMax QParser plugin to use a pluggable query string re-writer (via subclass extension) instead of hard-coding the logic currently embedded within it (i.e. the escape nearly everything logic). Additionally, I've made this QParser have a notion of a "simple" syntax (the default) or non-simple in which case some of the logic in this QParser doesn't occur because it's irrelevant (phrase boosting and min-should-max in particular). As part of my work I significantly moved the code around to make it clearer and more extensible. I also chose to rename it to suggest it's role as a parser for user queries.